RNA-dependent recruitment of the origin recognition complex.
The origin recognition complex (ORC) has an important function in determining the initiation sites of DNA replication. In higher eukaryotes, ORC lacks sequence-specific DNA binding, and the mechanisms of ORC recruitment and origin determination are poorly understood. ORC is recruited with high efficiency to the Epstein-Barr virus origin of plasmid replication (OriP) through a complex mechanism involving interactions with the virus-encoded EBNA1 protein. We present evidence that ORC recruitment to OriP and DNA replication function depends on RGG-like motifs, referred to as LR1 and LR2, in the EBNA1 amino-terminal domain. Moreover, we show that LR1 and LR2 recruitment of ORC is RNA dependent. HMGA1a, which can functionally substitute for LR1 and LR2 domain, can also recruit ORC in an RNA-dependent manner. EBNA1 and HMGA1a RGG motifs bound to structured G-rich RNA, as did ORC1 peptides, which interact with EBNA1. RNase A treatment of cellular chromatin released a fraction of the total ORC, suggesting that ORC association with chromatin, and possibly cellular origins, is stabilized by RNA. We propose that structural RNA molecules mediate ORC recruitment at some cellular and viral origins, similar to OriP.
Norseen
Julie
J
Program in Gene Expression and Regulation, The Wistar Institute, Philadelphia, PA 19104, USA.
Thomae
Andreas
A
Sridharan
Venkatesh
V
Aiyar
Ashok
A
Schepers
Aloys
A
Lieberman
Paul M
PM
D000595:Amino Acid Sequence; D002460:Cell Line; D002843:Chromatin / Q000378:metabolism; D004261:DNA Replication; D019309:Epstein-Barr Virus Nuclear Antigens / Q000235:genetics / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances / Q000378:metabolism*; D008969:Molecular Sequence Data; D051738:Origin Recognition Complex / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000235:genetics / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018741:Replication Origin
D002843:Chromatin; D019309:Epstein-Barr Virus Nuclear Antigens; D046911:Macromolecular Substances; D051738:Origin Recognition Complex; D011993:Recombinant Fusion Proteins; D012313:RNA; C417029:EBV-encoded nuclear antigen 1